On 2016-08-05 the 1.2 mag brightening of an otherwise quiet stellar source triggered the Gaia16aye Gaia Science Alert, nicknamed Ayers Rock (19:40:01.13 +30:07:53.4, J2000). The previous 22 Gaia detections of the source (starting from 2014-10-30) show no variability greater than 0.05m RMS. The initial spectrophotometric observations did not clarify the nature of the

Galaxy clusters are the largest and most recently formed cosmic structures in the universe, of which their content is expected to reflect the overall matter composition. They are dominated by the elusive substance that we call dark matter, but they also contain a smaller fraction of matter in the form of gas and stars. Although

Dark matter (DM) is one of the pillars of our cosmological understanding yet its nature is still elusive. It makes up about 85% of the Universe’ matter but its presence has been revealed only through gravity. The most interesting probes of its presence and nature is the merger of two clusters (or groups) of galaxies.